Abstract

Minimum coancestry mating with a maximum of one offspring per mating pair (MC1) is
compared with random mating schemes for populations with overlapping generations.
Optimum contribution selection is used, whereby ΔF is restricted. For schemes with ΔF restricted to 0.25% per year, 256 animals born per year and heritability of 0.25,
genetic gain increased with 18% compared with random mating. The effect of MC1 on
genetic gain decreased for larger schemes and schemes with a less stringent restriction
on inbreeding. Breeding schemes hardly changed when omitting the iteration on the
generation interval to find an optimum distribution of parents over age-classes, which
saves computer time, but inbreeding and genetic merit fluctuated more before the schemes
had reached a steady-state. When bulls were progeny tested, these progeny tested bulls
were selected instead of the young bulls, which led to increased generation intervals,
increased selection intensity of bulls and increased genetic gain (35% compared to
a scheme without progeny testing for random mating). The effect of MC1 decreased for
schemes with progeny testing. MC1 mating increased genetic gain from 11–18% for overlapping
and 1–4% for discrete generations, when comparing schemes with similar genetic gain
and size.